Nearly 13 years between 1994 and 2007, I wandered the streets of New York, a nomad in the town where I was born in 1949. To say that I was homeless is true and yet not the whole truth. I had a mobile home of sorts - my wagon - the most recent, a grocery cart I liberated from the Costco in Long Island City. In it, I carried everything I needed: bedding, clothes, a camp stove, beach chairs, an umbrella, pots and pans, a first-aid kit and 20 or so paperbacks.

Cadillac Man, a onetime policeman and divorced father of three, supports himself by collecting cans and assumes he'll end his life in an unmarked grave like most of his compatriots. Then, while setting up a little 9/11 memorial, he meets Carol. 25 years younger than he, a white-collar professional, Carol falls in love with him and the two build a life together, getting a small apartment in Queens where Cadillac Man builds a memoir from the notebooks he kept while living rough. Despite the indignities, the abuse, the sleeping in open graves, the many small tragedies of living on the margins of society, he has a certain nostalgia for his prior life.

At home with Carol, I have peace and love; I don't have to watch my back. But I also get claustrophobic. In the street, I had freedom, coming and going as I pleased. The streets are hard but they're my life's blood. I even write better there, with more energy in my stories. I try to return to the viaduct at least three times a week. The way some people commute to their jobs, I commute to my old spot on the sidewalk and catch up on the latest gossip.

The essay is a textbook reminder of the lives behind the faceless, and surely the memoir will be an even more powerful one. But just as striking is the philosophical way in which the author moves from life to life: what of his daughters, you wonder, his prior life? It seems the mental and emotional flexibilty needed to adjust to the existence of life on the streets in some ways means a level of stoicism that's as alien to most of us as the appeal of living off the grid. In a sense, he's illustrating the push-pulls of any relationship, writ large — freedom versus security and love? — and though the conflict may seem unthinkable to many of us — and evidently to his girlfriend, who worries he's "homeless in his heart." Maybe their definitions of "saving someone" differ.